Israeli officials said the strikes, in which three Palestinian children and their grandfather were among the dead, were in response to a recent mortar barrage fired by Gaza militants into Israel.

Reporting from Gaza City and Jerusalem — Israel launched attacks Tuesday against Palestinian militants in the Gaza Strip, killing eight people, including three children who were mistakenly hit by tank shells as they played soccer near their home, officials said.

Israeli officials said the strikes were in response to last weekend's barrage of more than 50 mortar shells fired by Gaza militants into southern Israel, injuring two people.

"We have no interest in escalation, but let's not forget, that was the largest number of mortar attacks we've sustained since the end of Operation Cast Lead," Israeli military spokesman Capt. Barak Raz said, referring to the 22-day Israeli offensive that ended in January 2009.

He said Israel regretted the children's deaths, but blamed Palestinian militants for using residential areas as a staging ground for attacks.

Relatives of the children, ages 9 to 13, reported seeing militants trying to use their neighborhood to launch shells shortly before the Israeli attack. The children's grandfather also was killed in the attack.

Officials with Hamas, the Islamist group that controls Gaza and participated in the recent mortar attack, accused Israel of "war crimes."

"We are doing our best to avoid violence with Israel, but the Israelis continue to escalate their aggressions against us," Hamas spokesman Sami abu Zuhri told reporters in Gaza.

In another attack Tuesday, four members of the rival militant group Islamic Jihad were killed by an Israeli airstrike as they drove in a car, witnesses said.

Israel also struck about half a dozen other targets earlier Tuesday, including smuggling tunnels and weapons caches. About 19 Palestinians were wounded in those attacks.

Palestinian Authority Prime Minister Salam Fayyad condemned the Israeli strikes and called upon the international community to intervene to restore calm. French government officials also called for restraint on both sides.